Typically, liners are used below casing in wellbores to extend the casing. A liner is a section of casing that is suspended downhole in existing casing. In most cases it extends downwardly into open hole and overlaps the existing casing by approximately 200-400 ft. The liner is sometimes cemented in place. In the past, hydraulic liner hangers have been preferred by operators in deviated wellbores over mechanical liner hangers. This is because the deviation in the wellbore makes it less certain that the hanger mechanism will be properly actuated in a deviated wellbore. Instead, well operators in deviated wellbores have preferred the hydraulically set liner hangers. In prior designs the liner with a setting tool would be lowered into position and pressure within the setting tool would be used to set the hydraulic liner hanger through a lateral port therein. In prior designs the flow passage through the setting tool would have to be obstructed at its lowermost end so that applied pressure in the setting tool would properly reach the hydraulic liner hanger. The obstruction for the setting tool would have to be near the bottom to allow a cement wiper plug the ability to pass completely through the setting tool and liner to remove residual cement therefrom. Alternatively, if the residual cement were not removed, cutting or grinding operations would have to be under-taken to remove any excess cement within the liner. Since a lateral port to the hydraulic liner hanger remained open in prior designs, an additional trip into the wellbore was necessary, subsequent to the setting of the hydraulic liner hanger, to properly position a setting tool for subsequent actuation of other downhole equipment attached to the liner, such as an external casing packer.
The operations involving prior designs lengthened the time required to complete the placement and cementing of a liner. Accordingly, the apparatus and method of the present invention were developed to improve techniques for setting hydraulic liner hangers. At the same time, the apparatus and method of the present invention were developed to allow in one operation the setting of the liner hanger while at the same time providing a clear path through the setting tool to allow the passage of cement wipers if the liner is cemented so that in one operation, the hydraulic liner hanger can be set and the liner cemented, as well as setting any casing or isolation packers attached to the liner.